If you ever need to raise money quickly you should battle the Trainers in the Nimbasa Stadiums (Big Stadium, Small Court) since you can rematch them every day.

Also, you can sell Everstones to the Gentleman in the Pokemon Center in Icirrus City. He'll give you 1,000 Pokedollars for each Everstone you sell him.

You can find Everstones easily by fighting Roggenrola in the Wellspring Cave, make sure you teach a Pokemon the move Thief (TM46) and you can steal Everstones off the Roggenrola, which hold them 50% of the time. If you're using a Gothita/Gothorita/Gothitelle it will be slightly easier thanks to their Frisk ability which makes them able to see the foe's held item.

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And no reptiles!
Just soft boiled eggs in shirts and ties
Waiting for the flashing green man